a) Field of the Invention
The present invention relates to a rotating window, and more particularly to a rotating window which is installed on a transparent glass of a CNC (Computer Numerically Controlled) machine tool or a transparent window of a ship.
b) Description of the Prior Art
A typical structure of a conventional rotating window has been disclosed in U.S. Pat. No. 5,161,055, wherein the rotating motor is located exactly at the center of the rotating glass (or transparent material), and a non-transparent housing member is fixed at the inner side of the rotating glass. The patent is provided with the following shortcomings after long time of usage:                (1) As the motor and the driving circuit take about one-fifth to one-sixth of the entire viewable area of the rotating window; therefore, when an operator needs to inspect by eyes a working status inside the CNC machine tool from the rotating glass, he or she will be usually blocked by the housing member to cause a bad vision, thereby being unavailable to completely observe the finishing status inside the CNC machine tool.        (2) The circular rotating glass rotates along with the central motor. However, if a working object inside the CNC machine tool slings off and hits on the rotating glass, the entire rotating glass will be ruptured and the frame which fixes the glass will be thrown out, thereby being capable of hurting people.        (3) As the motor is located exactly at the center of the rotating glass, it takes on extremely large circular area, and even occupies the transparent part of the rotating glass, as well as blocks the line of vision.        
Accordingly, how to provide a broader angle of vision for the rotating window, and to improve work safety, is a technical issue to be pursued by the present invention.